Cause Analysis and Observation of PVC Tape Transformation on Heated Steels
Naoya SHIGEMOTO, Motoaki SHIBAYAMA, Toshimitsu TAKAGI and Shinji NOGUCHI
Abstract:In October 2000, the 24 years old Ikata-1 PWR-type nuclear power plant suffered cracking in pipes, where poly vinyl chloride (PVC) tape had been placed and had become baked over time. The existence of residual stress over 100 Mpa in the pipes, a bit of chlorine and a feather like-pattern on the crack faces suggested the event was one of stress corrosion cracking. Engineers of Shikoku Electric Power Co. groups examined experimentally the production of chloride from PVC tape on a steel, and elucidated the temperature depending production peaks is induced by the properties of FeCl3, the principal ingredient of the chloride. Semi-quantitative expression of the production of soluble chlorine was proposed. In next report, authors will elucidate the stress corrosion cracking in steels with baked PVC tape and the cracking potential in pipes with the fluid of various temperatures and various duration. Key Words:Stress corrosion cracking, Poly vinyl chloride, Ferric chloride, Stainless steel, Atomic power plant, pipe